News in Brief Environment

Carbon dioxide levels hit landmark in Northern Hemisphere

Half the world sees full month at or above symbolic 400 parts per million CO2 level

SPEWING GAS  Burning fossil fuels spews carbon dioxide into the atmosphere. In April, CO2 levels reached a monthlong record of 400 parts per million across the Northern Hemisphere. 

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By Beth Mole

- More than 2 years ago

April was the first month in recorded history with average carbon dioxide levels at or above 400 parts per million across the Northern Hemisphere, according to a May 26 announcement by the World Meteorological Organization.